SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89f90a86213a3b8bfdccc4d71a4cc97e1cb6b0ef3fc623ff21fd67e74c56e27f' 
  AND token = 'MdlNEKCGQkPNOSLn6qUD336FmC689Xq6an2QZkAO2WQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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