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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9b0610844cc5b3386cdccb6ca5f7ae0bc39d5ab8f1438f5e37baa1258c40e1d' 
  AND token = 'HQOKqlUfILfgyy0X69m97ckxXdBGP0VbSxCnCbIjdf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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