SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6fff09a5e09bdcd8015a7ef6313e45250fe36a053b5e5aff91e837db47cfedc' 
  AND token = 'xQGdTdcWH7kMvb8wQhvX3niFjQf5VUJiL/RoXScE7Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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