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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d8dca45195aa48e9d4a8c32d71b3e1e75fd0ca9cd6efbb71be069be16dfbaae' 
  AND token = 'wDuTj+Uo0nDKdij+6fWQk7sEgmroVzXKCVA8ko/vFbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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