SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52c094760a6a14477e94673ed791906006d7aed56c8cb296b7d9b806bacacaf5' 
  AND token = 'dO8BfcYmb80yWSii7Kylb78m9QBI/PWoTNaY8Naya68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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