SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3df06d68e03104ca153cd80c27f80c4693f424d293e9bba4028edcf8112faa44' 
  AND token = 'g3wwo3gEFhjKOVkGB6IWvWHs59Qrf/LFXnjsIN4Y/0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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