SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b0c318a78bdd8bd3ff247ed8776ed40d90280e4a58ed02deaaa06fc4c5c1fd30' 
  AND token = 'bnunxz8AhYAo01gTPtajY8HTjAr/4frc/jCzzN/Ophg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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