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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42aa15a6715bda2087540ab6bf33c89032d58506b88c63e59ef61db788b2fe99' 
  AND token = 'iuZ+lsZ7Zer4X8fCOQFB2B0dYXZSfdF+o6+guW+KPOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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