SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e81135af0492b26947361c7df61503a8c0160bfb357fc4951dd8d035237f4af8' 
  AND token = '2y+ZBQnJgrbxvKWOOccDDhM2pPblvlE4wx6mE4PFDzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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