SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '677c2ffeb69b72c62fd03e5a8590542dd19886d1ba7dc5c12fbcbb026150d7a1' 
  AND token = 'Xpk+i9aacn6UKqeGqOtp5mLBOJ5+Vm48u3Nx8NlIYDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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