SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41c444a645057897f72f595e3466106c0cd03100a86855c624299330238f1595' 
  AND token = 'rJk0HNu7avn0HfxUhkhrhaSAYmy1xRWKt3BvGYsz47Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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