SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9753c448a33c72d7c8e04d89554f539440a3d82f40dd1eb4ccb73c75db3ed22' 
  AND token = 'K4fnt9wlQbYuD/bAD43cKbpeVnqjO5J2S7rATb5f7ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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