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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ca9a5992734ad80a51a8d9e647c019f9e42a81174b44aad04aa0c7e4ff77669' 
  AND token = 'wNjZWVU6gSIMs1vPlYBuOYx6IIj1XnXvszdSXTokQEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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