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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b4d1fd576b51d68b154a6d95eb5164fdb863cc5b388cbaf1f9a3033a9ed7d3c' 
  AND token = 'xc5OqK6PYMLcGUeaZvja7ThK3GvjsSbWHeg5Y4yydiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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