SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6395e53f937209b392a22fffd7ecfd3675776f9a3e74d976660b530bfae3f430' 
  AND token = '66nkNzdD2vW7mej8ONUueGEmCXsy0Zexx3DoXVPt28o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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