SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b395b15b03f266dd8574ffc9bd66aa792f21eb0b30ca168201ceee5d194523c6' 
  AND token = 'GsYiTItoR74LLTCv137ANmjIJNzHFAgs2tsxNaFgFmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}