SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c20082f071e04becaef842b15fa160590710578995beee86bb426bba497d101' 
  AND token = 'nubIeFbcPHoBEyyzZiXjw0CO+QQup8JHfY+39HfQGAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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