SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec2ce26442ff4af59d7986b38fca754b3a9cc89c27e898a6f26d93eb0736926b' 
  AND token = 't9tgtFJPZGXJsaRKv2UKJ063RVWNOyxS5joOmuUiX1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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