SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd135034dabb6896493c2b6a527b19960219abb90e90da68207e115ebb98554b2' 
  AND token = 'P4BjcTZltHTMcYdK0tUtboluNYwofU8Qx0To7IqDcHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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