SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5688db869d8cea9de8ab4da077f684884ad2f303dbbca439c69efdd056a953fc' 
  AND token = 'rGrOwOEeTNGRPt4aiAFhkRE7uQnx5lJm1NkDti86vzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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