SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09ecfa8da61eedd25da98f96ed3806ee219bf5331478872e0b894f1977a6dba7' 
  AND token = 'XSJ0kUAd4BdLzuwSdbtgjUTnrvapFZ0AYM54E1vbH6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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