SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '298c661cab8d1c826135e2a175d4c56c1747305a4fb492e817d73842595768d8' 
  AND token = 'Qd0QDRXIAH+f69Px6BBmbFLnYjlAct2xMhe1ZHKG380=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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