SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a63b4d02e3f1482f0dbb478138a1378f1f43f677adea8a04327a7113df821bf' 
  AND token = 'WgIPO025SkFNaVvWnVc/WVrUoCZ/H0mPBpbuR+Nxwxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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