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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9fac021504dfee765cbfdea4ca2252ab5c0edf17675b8d7f781ce9a03a188b4' 
  AND token = '79m7qwbI8X+IppjVx+QSDKJjn7uwOZ1nwPYHeNQPLaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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