SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b446dad9517cee849ec9d483c2bbec38c9317af3895befe4565d272ba6272ff0' 
  AND token = 'S/CKCIM1HVFD7dxiXCBC0tzc/LCqLUQDQpmIba+XfIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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