SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '10b599ef831868310dca85606042981e86a732d155cb7a3d1f244b3ca5986fe5' 
  AND token = 'BgQzRIDVRBscEq+lpdXGXPKr2nFwKqC68Ytg2AtLq1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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