SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c039fcfd42b97108851d1bbb0efe200c4aa5f9f0b1650ca204c47583153f09f0' 
  AND token = 'qmWmtsAmX5O/kpRCCSvz2Q5F2m0PhjsOMvC9r+UcxDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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