SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d15f2decfc76ec9127cbdeb109bbc21ee33168a8c9dc24051a7c6a25a0d9e5f' 
  AND token = 'o8PPYbFNYITZIwR2sScagBoWhxhNJOnB8nIkV3qLOi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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