SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a3f88e45090098b402f04c247dac9f2bca96653ef962212452138da0994af131' 
  AND token = '1rO8OJA6rycvm/z7pdrlWZdfpSfrt3d+fCM9dFXD5ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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