SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7686738e93a2a611492c3eac509ca852541ef9f9fc05da8be61f53f529215b6' 
  AND token = 'Z8jOLTfdTXGoEb57wH7V5MI3BCuLEZNcZmj8y7jMMZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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