SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e331da142351ef730eebf8be0bdca7cb6c5812f4b50354c8c612249e1b945d78' 
  AND token = 'hd7sp/KL5CWQAjZhg2Vj1VXw0rcHTsY3uQGGyhtvqPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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