SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '68799e6a114f897f110bdafe49c45acc4037d07fb76d291058abda6aed8c8e85' 
  AND token = 'TYR0OJLeE+RSGBn8mW6u+H7NiwntAkZYcCNBUNfudZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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