SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4210e6251e97bad886e92ee4101d30b89a880b98288cddc1b3d194f849fc1b10' 
  AND token = 'nLxq0+i2g+/NWIj6vJAwC/LgC97Y4T+IHJShwG2XBxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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