SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1751fb75bc6609d4305a01b812c871be24ef25343af675667aa58d0cfaf12a2' 
  AND token = '9jwQHB+aAqvTrnHrMNmvT1YeO2hf3Y/RsJVRMctSvIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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