SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd83f25177a4d38378464c6f77744e84394d72067cab1aa251fd9a50b99c2d78' 
  AND token = 'D+c2cPi9hsDqW4bqFqqsEwzkOnHTzmBHdg/osjnCVc8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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