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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2fb2e59f490c31901efeca6e485d80facaaeabac8870e010b4a9c477afd11549' 
  AND token = 'ex45nF0Is5ez81+dcze8K9DZ5Ef6sFB7Cb1rE4k+CUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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