SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1cb671f02decf5581693786bc9e8e24028edfc061815d36739594a7fb44c182' 
  AND token = 'af9aB63QFWVB9qpyPPEAAYUEwThctqwNIQvMyn/lk6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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