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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6672ab2640d98b89ec6e45a3c1d5508901d86dc42db364979ee9bbdb7e3e65af' 
  AND token = 'ERPGoPwXh2Hi4SFK9aCP6IcPc0vCVVhuKd0+NcL1RdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}