SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08f8d0a0dd28ba9fbffbf71edb2047b72a50e9dc06ff6d563e1e3c421661e1a0' 
  AND token = 'EbgXOKNUGVly8PKFBpqIiw6FCQQQDlE3M9oGYEWyPfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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