SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcfdb84fc0d2e35a977febcb636b7de1f1b2eff5557abccadc91e50ae9b6af84' 
  AND token = 'iDM9Bp2Zd9VH9HojdSE7x8wc9tja3iugiAaPk6Zl5OY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}