SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8639ee5526a7801b3f80f264d15f73391171b5fc60a9d7895426443be0a8effd' 
  AND token = 'OaozUcF8x4YyncdqQusa/9HU+mhm3xyu8Ey/bbr3BX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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