SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b59ba83a4e784d2ae24fb204337da95d5b6140e5e92a785c4c0015f12638c58b' 
  AND token = 'LELsryjV7vwRCE1b8PJJkqcy7jzaogmhTGfXtdpJiZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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