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SELECT 
  1 
FROM 
  q_lock_keys 
WHERE 
  key_id = '668aaec4f6ae0df5c19790882cfd41fe2313192febeffa0367941184e9eebee3' 
  AND token = 'UgOnW1QcMMzomz+JejOHXkhKYFWyi97KOrxbU3i/uFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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