SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8ddff33cb65e8551b02060712d37c51613f5d6567d94be34dea57ad5ac15d9e' 
  AND token = 'ybcwyUEbdSq68/CzHyAUl4YlWmNwZsVHNBbKixcHHkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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