SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6965c3c113ed4e89560b23130688990e57700f9162dcd2a5fe754c6e48ecdcc' 
  AND token = 'r+QHRzZgkYvCTKZzgU0Q8u/xumg3QaapXiKr//AGkXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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