SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab34c062efffa99c75c6dedfce209cf4577339b86211da02a0ee89f41aa038f4' 
  AND token = 'zZr+gu2CYMpl9aa8NtNCFt331xLW9woNRc26EyAizuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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