SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '148b517187680e91f395dff6fdf5c7082548e323a2af335cb59da35120e1cf56' 
  AND token = 'JQ6vwPah86Cz7FRsM5ufG8vCiQmqzbkrKLfzp91UBVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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