SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a50119d944a96a4ed7160314c293774f1279fb1da35865bd365897284c1efbc' 
  AND token = 'V39GLnE+uG3ViJ8lzrfedz4/IhP+iOhSdpNyTvy9M7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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