SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f10721999a692cdf434ac0a51a946b3a4072e0508de54da4e069a091d69d0ebf' 
  AND token = 'sJXi69HHZApVhPzfBJ4a0jBFv8eYjtaMauNQFuA0V9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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