SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9576186c6b8edf3f1dc1f2684fdcbaaf99feb01cba686b0b0bd5587cb9a9fd7b' 
  AND token = 'h3znIVv1KlsWIseCdmsMUzLXZ5SuVtsK5QrJi8KJBWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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