SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2a9eb7c218187f26c8602b63b43ef8864f6dd759eab86659314a090cabcf46b' 
  AND token = '4rBNy1e8kT/hQ3QYrElEagkSARiFXoj0HK5P3iXr6xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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