SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c67fb0973648b43f78694dec20df848b33c955464828f7bdc4a97ce4e7ff88d7' 
  AND token = 'RQazsvH9RrQxW1zDBDVjBNXfzJeHvAVy/CSEGdeLLKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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