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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3912933b59b1ec586dbdd23f7bf8e6b73ed21d2bd9f89f3395380a8b7bcf3490' 
  AND token = 'DJgl/FEPVVPSGysg/Xb4IP0Am80XIP/yDDv5tuMUwTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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