SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd6df4df2abb85d01b6108d2a3f33fa8337264df025bffd29b5db0f888056b768' 
  AND token = 'FzwFZcDM533qXwHvaiSUR3UGG+K9/zPGbjjxl8541Po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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