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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9c3565929e5b9456ecba3939c2c294a99965c3c1e3dfeb45eac4c8fc01b0cca' 
  AND token = 'KlgSGuG534wwBb3BYliPKi+vUssa2ZQQNgiCCMZTHyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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