SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b2b7db29976c7dc50a56da2a41a017efa5665abee7e02ab8c892890da2362a2' 
  AND token = 'aV1GmwwuAiyt/fb0nhZQKvzJ4NgjE9G3/VzvC+8EqCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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