SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffbb71615672e79b6c28daf5fdcc192e2cabbe2823189b45dedcddce6cb8c770' 
  AND token = 'BeoUWZE2YiAyG+Q4dAYepzKQWas6PpG9Ghe8ZR3iAsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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