SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bf40c17f72cf73c552d66f77459b969d3847f9bd9a4b16b79c8dfd3a5ad2ab1' 
  AND token = 'i6MxcYfqPvpxIdc4HefYbKQm2RDdOi7YtWjlSUKa8aw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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