SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b66e14b71156901905ef4575924e347edb51965cca1edac12561aac83c0c2bf9' 
  AND token = '7NtRi7NNCIpyncNp/HX8gIL5LCtWWMemmSS8YIGpjdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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