SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e3830d883cb17e31e28aa9bbc75e725c93851b1baa71066a89b69d31c5cbcd' 
  AND token = 'SJbDrI1Jwj7YqdVQiqz5op4T6yxtEyOhOqzPw0n7es4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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