SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8736c9dde4e4740207aad00bc64ba5e1fca459c634284091537b7bf3ef218215' 
  AND token = 'z/ybG/YS3wVixolS+zmDkZSIH7iurrcRdwBRi9FpBII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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