SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3de9c938519001cc4a23a2ef190a3e9c5749218f0be53af82a6b41afe3167df' 
  AND token = 'xOcy/978B7TYi9n1bndZzSZpdb6s0YLtRby5nJoiylU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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