SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '801f848d0f3aa07227d2a277353fef03904329d5c5a7286be69284a193c084d0' 
  AND token = '85rHHieiP9jaBz12KZKCwoj+JwgyZbInRmrY07DS+5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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