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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '314a95fcd75e6f944b749e09697d1980dc398f20cdd2b0ee6fbb7bae0fa2a458' 
  AND token = 'rSxAGHPcvqxPQP1PaAKmNjSB7PXLnv6OIA0iKeLxtmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}