SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5b6ceed4f3cc6669d82a159ad8acae32254d32a3ed06e78175e5d9055fed7b4' 
  AND token = 'rP5yaXhZxY6im2Kt4xxqNujIa8AW7aiqyFELxGoGzbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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