SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bceaafa0a00e72491229e7cd73528f55275a6b8ee4b76834eb2a46c00e800c4' 
  AND token = 'FwgAd9WwGnejO/MTdCzWxEPKAuAwrnteaCaq7YUlumQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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