SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8a297649db5e502a6c42e493cbdfc6c0e5c5f05d125c9a7c029068d381cb151' 
  AND token = 't9FKjhIGv7Jb2D+hRzulruuKGDZh7LUO0q7JN2fYQXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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