SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e20df410bffd206f5d650a6bd0665a2b756f65c2ece3d000c88725b68b9376e' 
  AND token = 'N/SSkhFHsNWT7LgvsqnWdbHgk1owS8SjWni1iCmfDzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}