SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b33a1bfa9ade51deba749797578b26990b95924aefa7cb0adaf44cc6c54815d' 
  AND token = 'rhmcDum3kzjOkKSQik31z4lTaOju5/ptBAEzTwYxi+4=' 
  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"
    }
  }
}