SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54c157dda641c660820b96db8cb0caabdbd6740e8da44c2709e89b9aa2295f44' 
  AND token = 's+K/a5CtLvfwX7i5IWCVXOEnwa5MaH9+f6/aDDMDm5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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