SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7c1521e86ad92c61c2c308908f4a78d69c64e7552bbb9832b17fb256c6af61b' 
  AND token = '2zFDFvz6e8TSUPFJDKPNe3jWyBmKvjVKSUMCk14SGlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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