SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd48cf999ab1d82ee75c23ced80b6a27b1e7d58ebd40562b28bb2e4bab77aea9a' 
  AND token = 'Fx942DuU0e/2ikZzp1Ul449IKo6WnXEBIkpYYzhLskU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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