SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea5522eb28d7cf84b2b947d2780069b3413c65074e584df12421392543340565' 
  AND token = 'jcO18M8EFs80bdrtv6wRSIpnsbTxUP1s6/yJuzNhY9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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