SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c66f68510bbc12e61f5d15f997ab317fbba34f6f0df323074ba0754caacc8c8d' 
  AND token = 'YXCRPeZiN1D4Gp2vF3wLTJOM1m+2EFrwNXkJQhnZovo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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