SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97313747c694f4e689546abb72e13dfe3e29b513acdb8fb064efd00f684f4653' 
  AND token = 'K273VoWVsmpxEb+d2x2FhDmQiB1ojqGfJeDZD9dP8Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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