SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2364fc67f57f2c096600eaa13d1cf06019efdfa5299729da3ea609a996f5b9a0' 
  AND token = '31vp5XtBrEaMZUJLYi250VBHDifxkxPkEeNhVsfThG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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