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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4d8f9342645cdb5c41df7f55b8c23ec6d85ca886162b874d54f6081a324f209' 
  AND token = 'gXCvU3Ws2sl9q8/Cm7aCsSXLQnJDaELW1uOjoCGdSGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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