SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4f3084045db427ac81712a5129e853173642cc180c8be334d50f8f15c9d4aaf' 
  AND token = 'x9llNCpEvyqAcXQlV+qngqDHN3yoJBLey8UVyfZ/YMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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