SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '435e9581f692b356d0ebc606e1f431f4891fa2ede238c5b8e355905e72f3f2e9' 
  AND token = 'B3Z2fgdiq6sxps94mZOQwq46CmJBzHGgATvIP3Fqwt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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