SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '286036693f6f053dce5e115d22ec7ab79f1231197a5cb2f6cc539690a18425f1' 
  AND token = 'qwNqv6mUb0h1rlPDyKW9fxdgnzj27NRtpBBUU777o0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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