SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e43a6ce62921ebc1abbec97a59027b74b767dadcbe90033ee3d8e201d057123' 
  AND token = '7TvU5kGrYbka0Gd66KEHYJ3OxL6yFPfORAR9tuDHDec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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