SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ba5093664d2e724c6aa5ce292734352278981918db38315311ad65e42ad5e7e' 
  AND token = '7Zuv38Q5jD7xk5KlZ4pfwQ/OlJHXlh+m+5BCEfcdfCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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