SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb510e279a0074cf93901872f9a3859c914462da01e31dd4c049f8d0d547f7ad' 
  AND token = 'AYiGdyvSHza5XxRt9k/kbmgBNigocuYlOzalp+6H+r4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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